@mixin prefixer($property, $value) {
  -webkit-#{$property}: $value; 
  -moz-#{$property}: $value; 
  -o-#{$property}: $value; 
  #{$property}: $value;
}

@mixin animation ($value) {
  @include prefixer($property: animation, $value: $value);
}


@mixin keyframes($animationName) {
  @keyframes #{$animationName} {
    @content;
  }
  @-webkit-keyframes #{$animationName} {
    @content; 
  }
  @-moz-keyframes #{$animationName} {
    @content; 
  }
  @-o-keyframes #{$animationName} {
    @content; 
  }
}

@mixin transition ($value...) {
  @if length($value) >= 1 { 
    @include prefixer($property: transition, $value: $value);
  } @else { 
    @include prefixer($property: transition, $value: all 0.15s ease-in 0.05s);
  }
}